


Another Day Like Today

by cassandraoftroy



Series: Only Time [1]
Category: Doctor Who (2005), Marvel Avengers Movies Universe, The Avengers (2012)
Genre: Action/Adventure, Crossover, Gen, Post-Movie(s), Spoilers, Timey-Wimey, Tony why do you take over stories that aren't about you?
Language: English
Status: Completed
Published: 2012-07-11
Updated: 2012-09-05
Packaged: 2017-11-09 15:19:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 9
Words: 15,055
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/456962
Author URL: https://archiveofourown.org/users/cassandraoftroy/pseuds/cassandraoftroy
Summary: <blockquote class="userstuff">
              <p>The day after the Chitauri invasion, Tony expects things to settle down and start returning to normal. He <i>doesn't</i> expect a certain blue box to show up on the roof of Stark Tower. And <i>nobody</i> expects what happens next! It looks like "normal" may be but a distant memory for the Avengers...</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Many thanks to cygna_hime for beta-reading this, and for commiserating with me when my tiny adorable plot-bunny turned into a three-part epic. (For the record, the original plot bunny is Part Two. It mutated into an enormous Plot Jackalope. Pity me.)

Tony stood on the landing pad, slid his thumbs through the belt loops of his jeans, and surveyed the damage. All in all, it could be worse: the rooftop of Stark Tower, where the Tesseract and its array had been set up to open the portal, was relatively clear. There was some debris, several pieces of broken Chitauri air chariots, and – _Gonna need to get a new satellite dish_ , he grumbled internally – but it wasn't nearly as bad as the chaos at street level. Construction and waste removal crews would be spending the next several days working around the clock to clear the streets of downtown Manhattan for traffic, to say nothing of the repairs most of the nearby buildings would require. Many of them would need to be demolished and rebuilt. _Not my problem_ , Tony thought with perverse cheer, and stepped down from the landing platform.

No work crews would be putting in an appearance up here, though; there had been more than enough intruders in Tony's private sanctum lately (beginning with the elevator full of sweaty workmen) that he would rather shift every piece of debris himself than bring more strangers through his penthouse. He bent down to heft a chunk of steel support beam that had come loose – and nearly pulled a groin muscle. "I _really_ need to finish the repairs on the suits," he growled, easing back into an upright position. He started calculating how long it would take before JARVIS finished machining his replacement parts.

"Can I help you with that?" The question cut through Tony's mental math, and he turned to find Captain America standing in the doorway leading from the penthouse. Or rather, to find Steve Rogers standing there, because the larger man was dressed in his preferred civilian attire of a button-down shirt and slacks, rather than the spangly costume. Tony's expression must have registered surprise, because Rogers jerked a thumb behind him and explained, "Miss – erm, _Ms._ Potts told me I could find you up here."

Tony made a mental note to discuss the new visitor policy with Pepper – _Namely, "warn me first."_ He shrugged. "I was just doing some tidying up out here. Wouldn't mind a hand, if you're offering."

Rogers crossed the intervening space, crouched to grab the support beam, and lifted it onto one shoulder. "Where do you want it?"

"Remind me to invite you over the next time I want to rearrange the furniture," Tony remarked. It took him a moment to realize that Rogers was waiting for his direction in order to put the huge metal beam down. "Oh, let's start a pile over here, out of the way."

"Sure thing," Rogers agreed, moving toward the corner of the roof that Tony indicated. "Thanks for lunch, by the way."

Tony waved off the thanks with a gesture. "Don't worry about it, Cap – can I call you Cap?"

"Or Steve," Rogers offered, setting the beam down gently against the raised strip of concrete that rimmed the rooftop.

"Didn't seem like you much cared for the shawarma, though."

Rogers shrugged. "It was just... very new. Like everything here." He turned to face Tony. "Stark, I know we didn't really get off on the right foot, before. I was wrong about–"

"I'm gonna stop you there, Cap, because I can see the direction this is going to go," Tony told him. "We both admit how much we misjudged one another, you apologize to me, I apologize to you, we share our feelings, we hug – and I don't know about you, but it's too early in the day for me to be drunk enough to have that conversation."

"That's not really an issue for me, since I can't get drunk," Rogers replied.

Tony recognized each of those words individually, but when he tried to string them together in his mind, they just turned to static. "Can't get drunk? Is that some kind of squeaky-clean 1940s honor-and-virtue thing?"

The look that Rogers shot him was familiar; Tony wondered if Pepper had taught it to him. "Hardly. Ever since the serum... my metabolism just burns off the alcohol before it can do anything." There was something in his voice that made Tony imagine what it must have been like for him, coping with waking up seventy years in the future without the benefit of a good stiff drink or five.

Tony shook his head. "And to think I ever regretted not having super powers. Anyway," he plowed on, "I don't see any reason we can't just forget the whole thing ever happened."

A small smile tugged at Rogers's mouth. "Sounds good to me." Then he paused, cocking his head to one side. "Do you hear that?"

At first, Tony didn't. But gradually, an unusual sound insinuated itself into his awareness. He was at a loss to identify it; the sound drifted somewhere between an almost musical hum and the groaning of friction, like someone had left the parking brake on... something. He turned to track the source of the noise, and found himself staring.

"Why is there suddenly a phone booth on my roof?" he demanded of no one in particular, pointing a finger at the offending object.

"I think it's a police call-box," Rogers corrected him. "P– someone told me about them during the war. They have them in London, for police to contact the station, or..." At Tony's raised eyebrow, he trailed off. "That should be _'had'_ , shouldn't it?"

"As fascinating as that little tidbit of British history is, it doesn't explain what the damn thing is doing on my roof."

As if in response to Tony's remark, the door of the booth opened, and out stepped a man in a bow tie and a jacket that must have looked outdated even to Rogers's eyes. He took two steps away from the box and stopped short, looking around in puzzlement. He turned all the way around, looked up at the sky, and then looked down over the edge of the roof. Only then did he turn his attention to the two men staring at him with wary alarm. "You know, I am rapidly beginning to suspect that this isn't Cardiff at all."


	2. Chapter 2

**Notes for the Chapter:**

> Here comes ~~trouble~~ plot!

When he'd first woken up to find himself in this strange future, Steve had been overwhelmed. He'd broken out of the almost-perfect replica of the 1940s that SHIELD had built for him and run, trying frantically to find a scrap of something that made sense in a world that was too fast, too loud, too big. Since then, he'd had other confusing and overwhelming confrontations with the world he now inhabited, but he'd adopted a new tactical approach to them: Wait and observe. Eventually, something would happen that would allow him to connect up what was happening to the things he already understood, and enable him to put the rest of the picture together.

So when the man in the bow tie and the British accent walked out of the London call-box on Stark's penthouse roof, Steve just stepped back and watched his teammate confront him.

"As a matter of fact, it's not Cardiff; it's _my roof_ ," Stark repeated. "Which, now that I mention it, _how did you get up here?"_

The odd stranger ignored the question, wandering to the edge of the roof and peering down at the city below. A broad smile crossed his face. "Are we in New York?" he asked Stark, looking at him over his shoulder.

Steve watched irritation war with confusion across Stark's features. There was no clear victor by the time Stark spoke again. "Yeah, this is New York City. Specifically, the roof of Stark Tower. _My roof._ "

The stranger's smile grew even brighter. "Smashing! I love New York! I even prefer it to New New York; it has a certain quaint twenty-first century charm."

Steve blinked at the notion of the twenty-first century, with all its fast-paced futuristic trappings, as "quaint." _Still waiting for things to start making sense,_ he told the universe. _Any time would be good._ Oddly, though, he wasn't experiencing the uneasy tension he usually felt when things took a turn for the strange. Steve had a well-developed danger sense when it came to other people. However bizarre and unpredictable the man in the bow tie was, Steve was confident that he was entirely without malice.

Unsurprisingly, Stark wasn't nearly so content to sit back and wait when the world around him needed a good dose of logic. "Okay, let's start again. _What the hell are you doing on my roof?"_

As though hearing the question for the first time, the stranger turned to face him. "You know, that is an excellent question. I can't imagine what could have pulled the TARDIS off course." He turned his head to regard the blue call-box, then snapped back toward Steve and Stark. "There hasn't been any sort of enormous discharge of energy around here, has there?" he asked, making an incomprehensible gesture with his hands. "Something that might have disrupted the fabric of time and space?"

There it was: the one detail that made the picture start to pull into focus. "The Tesseract!" Steve exclaimed. 

"Yes, that would do it," the strange man agreed. "Any significant discharge from that would have eclipsed the energy output of the Rift, pulling the TARDIS here instead of to Cardiff." Then the man blinked, as if he'd only just heard everything that Steve had said. "The Tesseract? Little boxy thing, about so big? Generates more energy than every power station on this planet, combined?"

"You know about the Tesseract?" Stark demanded, stepping forward.

"Certainly, though I'm rather surprised that _you_ do; it should never have been on this planet to begin with. What was it doing here?"

"Causing trouble," Steve put in.

The stranger smiled at him. "Well, yes, it would do, wouldn't it? Is it still here?" he asked, glancing around.

"It's gone," Stark told him, steel threading through his voice. From the tense lines of his body and the suspicion burning in his eyes, it was clear that Iron Man didn't share Steve's assessment of the stranger's motives. "But I'd still like to know who you are and how you got here."

"Right, of course." The stranger faced them, still smiling broadly. He offered a friendly wave. "Hello. I'm the Doctor."

He said it as though the word were explanation enough. For Stark, it clearly wasn't. "Okay, Doc, how did you get up here? After yesterday, this building has a bigger security detail than the White House; there's no way you slipped past them _and_ my electronic security measures."

"You're quite right about that," the Doctor agreed cheerfully, crossing his arms and leaning back against the blue booth. "I didn't come through the building. I came in the TARDIS."

Stark stared at the Doctor for a moment. "You'd be surprised how unhelpful that explanation is."

The Doctor gestured with one hand in a vague shrug. "Unfortunately, the more detailed explanation might be a bit over your heads. The TARDIS is a stunningly complex device, well beyond your human technology, and requires a truly brilliant intellect to operate or understand."

"I'm a pretty smart guy," Stark deadpanned. "Try me."

The Doctor bristled. "Very well, then. TARDIS. Time And Relative Dimension In Space. A dimensionally transcendental biotechnological capsule capable of traversing the time vortex."

"It's a time machine?" Stark blurted.

 _That_ snapped Steve's wandering attention back to the conversation in front of him. While Stark battered the Doctor with questions about the many-worlds hypothesis and quantum realities and space-time geometries and wormholes other phrases that made no sense to Steve, the blue police call-box drew Steve's focus to it. _A time machine._ Possibilities swam before his mind's eye: Dr. Erskine. Bucky. _Peggy..._

He didn't have long to dwell on the image of dark eyes, full lips, and perfect brown curls that flashed through his mind, however; an insistent beeping noise at his hip yanked him out of his reverie. Someone was trying to contact him on his SHIELD-issue telephone.

People always expected him to be baffled by twenty-first century technology – and in fairness, a lot of it was rather overwhelming – but he didn't understand what was so surprising about his ability to operate a telephone. The basic function of a telephone was the same back in his day, and the ways they had changed actually made them _easier_ to use, not harder. Touch-tone number buttons were a distinct improvement over the rotary dial, for one thing. Sure, the telephones were smaller and didn't need a cord, which was impressive and all, but "push the green button and talk" was an instruction a dancing monkey could follow. _Well, except for the talking part,_ he amended.

He pushed the green button and brought the telephone to his ear, taking a few steps away from the spirited discussion between Stark and the alleged time-traveler. "Rogers here," he told the phone.

"Captain," Nick Fury's voice was hard and sharp over the telephone line. "Assemble your team. We've got a problem. Get to Penn Station, ASAP."

"On our way," Steve replied automatically, already moving toward Stark. "What's the problem?"

"Our intel is sketchy, but you'll know it when you see it. Get ready for a fight," Fury warned, and then the line disconnected.

Steve slipped the telephone back into his pocket. Stark was embroiled in some sort of argument with the Doctor, but from the tone, Steve could tell is wasn't the angry, distrustful, get-off-my-roof sort of argument he'd been expecting before. They were tossing around a lot of science words that Steve couldn't have defined for love or money. Stark seemed to be having _fun_ , and Steve almost regretted the need to interrupt.

He clapped Stark lightly on the shoulder. "Time to suit up. We've got trouble."

Stark half-turned to face him, part of his attention clearly still on the other man. "No, no, no, Cap. Trouble was yesterday. _Time travel_ is today."

For the first time since meeting the man, Steve found himself willing to believe that Tony Stark was actually significantly younger than himself. "Time travel can be for later. Right now, we have a job to do, Iron Man."

Using the name did the job. Stark squared his shoulders and nodded, before pulling out his own telephone and pressing a button. "JARVIS, are those new parts done yet? Good; prep the suit. I'll be right down." Then he turned and pointed at the blue time machine. "That thing better be here when I get back, Doc. I still want a look inside."

"I've got an even better idea," the Doctor replied. "Why don't I tag along with you lads?"

Steve shook his head. "It's going to be dangerous; we were told to expect a fight."

The Doctor waved off his concern. "Don't you worry about me! After eleven hundred years of time and space, I've learned a thing or two about looking after myself."

Steve chose to ignore that bit of information until he had the time to process it. "All right, but stay out of our way." He turned and headed for the door back inside and the elevator beyond, with the other two men following close behind.


	3. Chapter 3

JARVIS had already integrated the new components into the Mark VII by the time Tony got down to the workshop. Normally he preferred to sand down the rough edges by hand before installing new parts into the armor, but time (and global crises) waited for no man. "Maybe this one won't be a _global_ crisis," Tony speculated. "Maybe Fury just wants an excuse to play with his shiny new superhero team. I know _I_ would."

"Yes, sir," JARVIS responded drily. "One assumes that to be the reason you have not yet been offered a position within the SHIELD command structure."

"You have no sense of fun, JARVIS. How did I ever manage to build an AI with no sense of fun?"

"One of the great technological mysteries of our time, Sir."

Tony rolled his eyes as he clasped the Mark VII's sensor bracelets around his wrists, and then gave the command for the suit to assemble around him. "Did you finish the tests on the material strength of the alloy formulation for the new parts?"

"Parts made using the new gold-titanium alloy formulation slightly outperformed theoretical projections in bench tests, in both compressive and impact strength," JARVIS replied. "However, your models accurately predicted its resistance to torsional stress."

Tony grinned; JARVIS was better at keeping up with Tony's sudden changes of topic than most humans were. "Excellent. Time for some field-testing."

"Do be careful, Sir."

The faceplate of the Iron Man suit snapped shut. "Aren't I always?"

JARVIS's response came through over the speakers inside his helmet. "My database does not contain a dictionary that lists a definition for the word consistent with your usual behavior patterns. Shall I consult Google?" the AI offered. "Or perhaps UrbanDictionary?"

"No sense of fun, but a gift for biting sarcasm," Tony observed, heading for the hatch designed for workshop launches. "How _do_ you manage it?"

"Years of adaptive programming, Sir," JARVIS replied in his ear as Tony engaged the repulsors and took off.

He cleared Stark Tower and maneuvered his way between two of the nearby buildings. "Did Cap manage to contact the others?" he asked.

There was a brief pause before JARVIS responded. "Call records from Captain Rogers's mobile phone show calls successfully placed to Agents Romanov and Barton and Dr. Banner within the past two minutes, Sir."

"Too bad there's no way of getting in touch with Mr. Renaissance Faire – though he's probably busy testifying at his brother's war crimes tribunal, or whatever passes for a justice system up there. Guess we'll just have to pick up the slack, won't we, JARVIS?"

"Indeed, Sir."

Tony decided that it really was much easier getting around New York City when he didn't have to worry about little things like cars and pedestrians. Which was fortunate, in light of the massive torrent of panicked humanity pouring forth from the main bank of entrances to Pennsylvania Station. 

Tony's HUD singled out a familiar motorcycle on the sidewalk near the front of the building; it had been knocked over in the pandemonium. A rope dangling from one of Barton's grappling arrows embedded in the wall beside a smashed-in upper level window told Tony that the other Avengers were already inside. He shifted direction with practiced ease, angling toward the window to follow them, when he noticed something else.

At street level, it must have seemed like pure chaos, but hovering on a level with the nearby rooftops, Tony could see the individual figures blur into smooth lines of motion, streaming along paths of least resistance through the sidewalks and streets, flowing around stopped cars and other small obstacles. But half a block away, something larger interrupted the flow of human motion, knotting up the streams and forcing them to divert around it. Tony took it for a sinkhole at first, centered in the middle of the west-bound side of 33rd Street, but a closer look made him reject that possibility; the symmetry and radial cracking in the asphalt suggested an impact crater.

 _Impact from what?_ Tony wondered. He aimed his repulsors downward, bringing him closer to the crater. "JARVIS, did that show up in the damage assessment we got from SHIELD this morning?"

"It did not, Sir," JARVIS replied promptly. "Moreover, elevated temperature readings in the immediate area suggest that the crater was formed within the last thirty minutes. Closer inspection could yield a more precise estimate."

"I think it's safe to say that whatever happened here did it about thirty seconds before Cap's phone rang," Tony retorted. "I'm more interested in what it was. Any thoughts?"

The targeting scanner on his HUD highlighted the roughly circular hole in the center of the crater. "There is an opening, approximately 4.2 meters in diameter, which appears to extend below the level of the street. It is not possible to determine its depth from this distance," JARVIS offered.

"Only one way to find out." Heedless of JARVIS's admonitions of caution, he dove for the tunnel.

The passage didn't curve on the way down or vary in width, though it entered the ground at a slight angle. Tony tried to remember how far below ground the terminal's train and subway platforms extended – before he realized that he'd never actually _ridden_ a train or the subway. _Right, private jets and a personal driver. How do I forget these things?_ Before he could ask JARVIS to pull up schematics of the Manhattan railway system, he reached the end of the tunnel.

Tony could only speculate that the thing at the bottom was some sort of vehicle or transport. It had punched through into a lower-level platform, and tipped partway out into the open space beyond the tunnel. It was much longer than it was wide, and listed heavily to one side like a bizarrely futuristic reimagining of the Tower of Pisa, but its precarious angle left enough of a gap for the Iron Man suit to slide between the transport and the crumbling brick of the platform wall.

It was a tight fit for the armor, but Tony figured that these wouldn't be the only scratches in the finish by the time he got back to Stark Tower. He could hear the sounds of combat in progress echoing through the space beyond. "Am I late to the party?" he asked as he managed to squirm free of the tunnel. "I hope you guys saved me some –" He stared at the scene before him. "– giant six-legged lizard men?"

The shock only lasted for a moment. _Not meaningfully weirder than the Chitauri,_ he decided, and let his HUD show him the scene. He could see three of his teammates, plus the time-traveling stranger; Barton had staked out a position on the stairwell, giving him a clear view of the entire platform, and was taking shots as he saw them. Evidence of his handiwork lay on the concrete floor; one of the reptilian creatures lay sprawled and unmoving, with its weapon half covered by its elongated torso and the shaft of an arrow protruding from an eye socket. Natasha was a blur across the battlefield, diving and somersaulting as often as she ran, dodging blasts from the energy weapons wielded by the lizard men. The Doctor had ducked behind a trash can, and was clutching something that looked like an unnecessarily large and unwieldy pen. And Cap was in the thick of it, barking orders as he stepped out from behind cover to throw his shield or draw fire away from Natasha.

Cap glanced up at Tony as he maneuvered around a collapsed section of wall and skimmed low over the platform to join his team. "Nice of you to join us," Cap remarked, reaching up to catch his shield as it ricocheted off a lizard-man gun and flew back toward him.

"Well, it was either this or play Go Fish with Dummy until you guys got back," Tony replied, dodging a shot from the oversized ray gun wielded by the nearest lizard man. "And he cheats." He held out a hand, unleashing a repulsor blast from his palm at the lizard man. The blow knocked the creature off its four feet, but it clung to its weapon with its two highest limbs.

Counting the single casualty that Hawkeye had managed to inflict, there were eight of the reptile people in total. A couple of them stood upright on their rearmost pair of legs, using their thick tails for balance, which gave them four hands to use for holding weapons or, in one case, tending to an injured comrade. The rest assumed a quadrupedal posture, which still gave them two dextrous limbs to aim their guns with. Their snouts were covered by what Tony guessed were breathing masks, and two large, spiny fins sprouted from their backs. _Not weirder than the Chitauri, but only just,_ Tony decided.

He flew a little higher, lining up two simultaneous shots. One knocked the legs out from under the lizard man coming up behind Natasha as she fought another of the creatures, and the other blast knocked away the gun belonging to the lizard man at the edge of the platform, who had been aiming a continued discharge from his weapon at the subway rails, for reasons that Tony didn't have time to care about.

That drew the things' attention. One of them leveled its ray gun at Tony and got off a shot before he could react. He braced himself for any of several possible consequences: being hurled back into the brick wall on the other side of the platform, being electrocuted, having a smoking hole blasted in his armor...

What he didn't expect was for his HUD to go dark, his repulsors to cut out completely, and the armor to drop like a rock onto the concrete. The steady thrumming of his arc reactor was gone, and Tony couldn't tell if his inability to breathe was due to panic, imminent cardiac arrest, or the failure of the suit's internal atmospheric system. He struggled against the suddenly suffocating weight of his own armor, trying to raise his arm enough to lift the faceplate of his helmet. When he managed to pry it up, he had to squeeze his eyes shut against the dazzling torrent of energy pouring into him in a steady stream from the lizard man's weapon.

Then the blinding light and prickling static across his skin stopped, and Tony felt the arc reactor hum to life again in his chest. He lifted his head to find himself lying in the reassuringly large shadow of Captain America. Cap's shield was raised in front of him, reflecting the beam from the lizard creature's gun up into the ceiling. The dim overhead lights flickered and died.

"Iron Man, get out of here!" Cap shouted over his shoulder. "Get upstairs and help Banner with crowd control!"

Tony got a knee under him, and pushed himself to his feet behind Cap. The power display in his HUD read 26% and rising. "I'm fine," he argued. "I'll be back to full power in about a minute."

"This isn't a discussion," Cap growled. "You're out of this fight. Now get up there and make sure the civilians don't trample each other to death on the way out of the building!"

His armored gauntlets curled into fists, but the part of Tony that was still reeling from having the arc reactor shut down knew that all Cap had to do to win this argument was move his shield and step aside. Swallowing an angry retort, Tony engaged his repulsors and shot off toward the staircase, twisting in midair once to dodge a weapon blast and again to avoid colliding with Hawkeye on the steps.


	4. Chapter 4

Steve waited until he was sure that Iron Man was clear of the platform before stepping to one side, behind a support column, and lowering his shield. The beam of energy he had been reflecting off the vibranium surface shot past him, striking the concrete floor for a handful of seconds before the alien – _And when did 'aliens' become normal?_ Steve wondered; _Is this gonna be an everyday thing now?_ – disengaged the weapon. The fluorescent lights embedded in the ceiling flickered a few times as they came back on.

"Looks like their weapons can disrupt electricity," he shouted to his team. It probably wouldn't matter much to Hawkeye, but he remembered that the Black Widow had some gear that might be affected.

"No, that's not quite right," came the Doctor's voice from a few yards behind him. Steve spared a glance over his shoulder, and spotted the smaller man ducked behind a garbage can, fiddling with some sort of device.

"You know these things, Doctor?" he called.

"Well, no," the Doctor began, "I mean yes, but – well listen, when you've been traveling the universe for over a thousand years, see if _you_ remember every encounter with an alien race in perfect detail!"

"Anything you can tell us would be great," Steve prompted, rising from his half-crouch to throw his shield. He took the legs out from under one of the aliens assuming a bipedal posture, before it could leap at Black Widow. She spun around, landing in a crouch beside its head, and drove her knuckles into its throat with a wet _crunch_. The shield skittered along the concrete, collided with another support pillar, and was kicked up into the air. Steve caught it neatly as it flew past his head.

Two more aliens were converging on the Widow's position. They seemed to be focusing their efforts on her, though whether as the greatest threat or the most exposed target, Steve wasn't sure. She was holding her own out there, but most of her best moves were intended for opponents with only two arms and two legs. He glanced at his teammate's face; she swept her gaze over one of the aliens, planning in the space of a heartbeat how she would take the enemy down. The other alien was behind her, and Steve didn't have a clear shot from his position. He glanced up at the ceiling, estimated angles, and threw.

The shield spun edge-on into the ceiling, shattering one of the glowing fluorescent tubes overhead as it ricocheted and hurtled into the skull of the alien advancing on Black Widow. The alien dropped like a marionette with its strings cut, and the shield clattered away across the concrete.

"Go easy on the lights!" The sound of Hawkeye's voice, just loud enough to carry across the platform, distracted Steve from seeing the Widow dispatch her other assailant. "Trying to line up a shot really sucks when your team thinks the fight needs mood lighting."

The Doctor bolted to his feet – only to duck back down, narrowly avoiding a blast from one of the alien weapons. "That's it! Sucking!" he exclaimed. "You! You're brilliant – whoever you are; I don't think we've been formally introduced."

"You have something, Doctor?" Steve struggled to drag him back on task.

"Their weapons," the Doctor explained, "they don't disrupt energy, they _absorb_ it. They're collection devices. The Ketaros use them to–"

Steve held up a hand to forestall the lengthy explanation he sensed coming. "Save the details for the debrief. What do I need to know _now?_ Can those things hurt us?"

"They can't absorb energy from most forms of biological life," the Doctor replied. "Electromagnetic, some chemical, some radiation, but their energy collectors aren't optimized for living beings. Might feel a bit funny, but–"

"Good," Steve said, and darted out from cover toward his shield. It had landed facedown; he didn't even have to pause, snatching it up as he ran by. He kept his momentum up, barreling into one of the aliens that still had its gun. It fired a shot at him before he connected; the energy splashed over him, and a sensation like intense static cling crackled over the skin of his entire body, _pulling_ at him. But otherwise, nothing happened. He collided with the alien, shield-first. It was like body-checking a horse, but he managed to knock it off-balance, and they went down in a tangle of limbs.

The alien held onto its weapon, holding it across its body with its upper set of arms to block Steve's blows. The lower arms began trying to pummel Steve's body around his shield. He got his knees under him, straddling the alien's abdomen, and aimed a couple of punches at its head. It brought the rifle up to intercept, and his fist grazed harmlessly off the metal.

He rose up on his knees, and then dropped back down _hard_ , landing right where his opponent's solar plexus would be, if it were human. Apparently its anatomy was at least vaguely comparable, because the alien exhaled loudly into its breathing mask and its arms went limp for a moment. Steve took that opening, yanking away the gun and landing a quick series of punches to the alien's face and chest. He ended by slamming its head into the concrete floor beneath them until its muscles slackened and its eyes rolled back.

"Psst!" He glanced up; the Doctor had sneaked closer during the scuffle, and was hiding behind another support column. He waved for Steve to join him.

He rolled off the unconscious alien and was crouched by the Doctor's side a moment later. "You have something?"

The Doctor nodded; he was fussing with an odd device about the size of a cigar. "I think I've found the right setting to disrupt their energy collectors. If I can shut down their weapons, perhaps we can convince them to surrender."

Steve glanced over the top edge of his shield at the remaining aliens. The one whose gun had been blasted away by Iron Man had closed in on the Black Widow, while the others seemed to be searching the area, firing their weapons into walls, ceilings, and pretty much anything else on the platform. "These guys don't seem like the surrendering type," he observed, "and I doubt they speak English. But give it a try; it might at least prevent some property damage."

"Actually, the TARDIS telepathically translates any spoken language for me, so I'm not actually speaking–" The Doctor looked up at Steve. "You know what, why don't we just go ahead and save that bit of explanation for a better time, shall we? Let's try this." He stepped out from behind the column and leveled the device at one of the aliens. The tip glowed green, and the device let out a high-pitched whirring sound. The flashy high-tech visuals Steve had been expecting didn't happen, but the alien's weapon went dead in its hands. It growled down at the gun, trying to fire it a few times, with no effect.

Its still-armed compatriot leveled its weapon at the Doctor and fired. The green light at the end of his little device winked out as the Doctor was knocked off his feet by the blast of hungry energy. Then the alien whose gun had been disabled cast it aside with a clatter and advanced on him, clenching its four fists.

An arrow shaft sprouted from its breathing mask. The alien went down heavily, clutching at its face with its upper hands for a few moments, before it went still. The Doctor scuttled back behind the safety of the support pillar, where he began tinkering with his inert device. "Well that was a splendid idea while it lasted," he declared, smacking the side of the device with the heel of his hand.

With the civilian back behind cover (because no matter how many centuries' experience with time travel and aliens the man claimed to have, the Doctor was a civilian in Steve's mind), Steve shifted his attention back to the fight. Two of the aliens were still standing – no, make that one; the Black Widow had somersaulted over her opponent's head to land seated on its shoulders, her thighs around its head. She wrenched her hips around, and there was an audible _pop_ as something important in the alien's neck gave out.

The last alien found itself on the wrong end of Steve's shield. It brought its weapon up to protect its head from the whirling disk, but the force of the impact knocked the rifle from its grasp. It wasn't ready for the overhead blow from a metal trash can that followed immediately after, and it toppled amid a rain of crumpled newspaper and fast food wrappers.

Steve set the heavily-dented garbage can back beside the pillar where he'd found it. "A SHIELD team should be here soon to clean up," he observed. "Let's round up the others and get back to Headquarters; the Doctor has some intel we're all going to need to hear."


	5. Chapter 5

The minute they passed through the doorway of the briefing room, Stark ripped his helmet off and rounded on Steve; for an instant, Steve actually thought the helmet was going to come flying at him. “I’m either on this team or I’m not, Rogers,” he snarled. “We’re not out there playing Little League – don’t bring me into a fight and then _bench_ me at the first sign of trouble.”

Steve felt his own hackles rising in response to the heat in Stark’s voice. “First sign of—? Are you _insane?_ One shot from their weapons almost completely drained your arc reactor. Which, if I remember my briefing memos right, not only powers the suit, but _keeps your heart beating._ I made the right call for the mission, and if that hurts your ego, that’s not my problem.”

He felt the other Avengers take up alert postures, responding to Stark’s confrontational stance. “I single-handedly enforced world peace for six months before being tapped by the Avengers Initiative. If that’s not good enough for you, if you don’t think I can cut it out there, you just tell me now.”

An angry retort was halfway out of Steve’s mouth before he bit it back. There was something different about Stark’s attitude this time, something that hadn’t been there in the argument on the Helicarrier. He studied the other man: dark eyes defiant, chin thrust out as if inviting – no, expecting – a blow. Stark’s words echoed through his head; _not good enough, can’t cut it._ Steve felt his eyes widen as he realized what was going on. _Is he afraid we’re going to reject him?_

He’d seen it enough during the war. Injured soldiers fighting the orders to be shipped home, out of fear of losing the respect of the men they’d bonded with, bled with, on the battlefield. Why Tony Stark should feel that way eluded him, but that's where all the signs pointed. Though he could still feel the adrenaline coursing through his system, Steve’s anger abruptly drained out of him. “Of course you’re part of this team, Iron Man. This entire city would be a smoking crater if you hadn’t been here yesterday. But all of us have vulnerabilities – _all of us._ And today we ran into yours. Tomorrow it’ll be someone else’s turn. That’s part of the reason for having a team.”

Stark let out a derisive snort. “Sure, ‘all of us’ have weaknesses, he says to the guy on a team with a supersoldier and a _godling.”_

“You think Thor doesn’t have any weaknesses?” Steve let his incredulity show in his tone. “You saw the same footage that I did from the fight on the Helicarrier. Thor’s not stupid, but he’s…” he fished for a word, “…very straight-forward. You don’t exactly have to be an alien trickster god to put one over on him.”

“And the Big Guy?” Stark demanded. “He’d make road pizza out of anyone trying to pull a fast one on him.”

Steve briefly glanced around the conference room; it seemed that Dr. Banner had wisely removed himself from the area at the first signs of a heated argument. “That one’s even easier,” he pointed out. “The Hulk can’t cope with any problem that can’t be solved by smashing it. With anything requiring delicate work or complex thought, he’s useless. Not to mention the effort that Dr. Banner has to maintain to keep from changing at the wrong time.”

“Well, sure,” Tony conceded, “but you can’t say the same about our resident secret-agent duo here; they don’t have any double-edged superpowers to be exploited.”

A brief flick of his gaze showed Barton staring at the floor, shoulders tense. He didn’t know the archer well yet, but he could guess at what was on Hawkeye’s mind: the way he’d been compromised by Loki. Stark wasn’t the only one who needed reassurance, but Steve doubted that Barton would accept any direct words of comfort from him just yet. “Range,” he said simply. “Hawkeye is an unbeatable shot at a distance, but that advantage disappears in close quarters. He’s good hand-to-hand, but there are others who are better.” He thought he saw Barton’s shoulders relax just a fraction.

“I doubt you’ll be able to come up with anything for Miss Romanov,” Stark dared. “I’ve known her for a while now, and she’s never shown any sign of being less than practically perfect in every way.”

Steve had to admit that, in the little experience he’d had with Natasha Romanov thus far, that description was pretty apt. “That just means that we’ve only seen her in situations that have played to her strengths,” he temporized. “It can take time to get to know a teammate well enough to learn where they have trouble. But everyone has something.”

To his surprise, he heard the muffled tap of heeled boots on the carpeted floor as Natasha crossed the room toward him. The expression she wore was even more surprising: on anyone else, Steve would have described it as uneasy, even anxious. She stopped a few feet away from him and looked up into his face. “You’re right,” she said simply, her voice soft. “Everyone has something. Even me.”

Steve shot a glare at Stark to keep him quiet, but apparently he was either too shocked or too curious to interrupt, for once. After a single deep breath, Natasha continued. “I’m telling you this because I understand the necessity. As team leader, you have to be able to anticipate our reactions, and… plan for all eventualities.” Steve could have sworn he saw her _not_ glance at Barton.

At Steve’s nod, she went on. Her back was almost painfully straight as she spoke, and she locked her eyes on his. “I have a severe phobia,” she said. “It was instilled in me as a conditioning tool, by the people who made me what I am. It is specific enough that they could reasonably expect I wouldn't encounter it on missions, but it gave them an effective means of enforcing compliance during my training.” She dropped her gaze. “I’ll tell you what it is later. In private.”

“Of course,” he told her. “I know how much trust it took to tell me that. Thank you.”

“Deserve it.” She stepped around him and left the room.

Stark broke the stillness that descended on the room in her wake. “I guess that just leaves you, Cap,” he observed. “Are you gonna try to convince me that the great Captain America has some major weakness that leaves him as vulnerable as the rest of us mere mortals?” Steve caught the sharp edge in his voice, the trepidation nibbling at the fringes of his sarcasm.

He remained silent for a moment, studying Tony Stark, trying to come to a decision. Something in his face must have changed, because the challenge slowly melted from Stark’s expression, leaving a more serious countenance behind. “You want to know what my vulnerability is?” he asked quietly. Steve felt, more than saw, the three remaining pairs of eyes in the room focus on him; Barton looked up at him from his perch on the edge of the conference table. The Doctor gazed at him over the top of his disassembled screwdriver with eyes far older than they had any right to be. And Tony Stark simply nodded.

“It’s losing people,” Steve said. “Every time, it takes something out of me, something I don’t think I can ever get back. I’ve lost so many people.” Images flickered across his mind's eye: his mother's sick-bed. Blood on the laboratory floor. The train car on the snowy mountainside. Red lips and dark curls. “Everyone from my time. And then…” He didn’t need to say Coulson’s name. It was already hanging in the air, a palpable weight on the shoulders of the team. “I don’t know how many more times I can do it.”

He stepped forward, closing the distance between himself and Stark, and grasped both shoulders of the Iron Man armor. “So you watch your ass out there, don’t take any more stupid chances than you need to, and follow orders when I pull you out of a fight. Got it?”

Stark’s Adam’s-apple twitched as he swallowed hard. Then something shifted in his eyes, and it was like the entire conversation hadn’t happened. “Right; you got it. You’re the boss, Cap.” He backed out of Steve’s grip, and then headed for the door. “I’m gonna go track down the rest of our merry band, before Fury gets here and only finds half a team to debrief. If I’m not back in ten minutes, check by the coffee machine in the break room. I think I saw donuts on the way in.” He was out the door before Steve could reply.

Barton stood up. “He’ll never come back if I don’t tag along,” he offered, jerking his thumb in the direction Stark had exited. “Besides, I have a pretty good guess where to find Natasha.”

Steve nodded. “Go ahead. If Director Fury comes to debrief us before you get back, I’ll… make something up.”

That prodded a laugh out of the archer. “That, I’d like to see. Gives me incentive to get back sooner.”

When Barton had gone, Steve turned to face the room’s only other occupant. The Doctor twisted his screwdriver back together and pointed it at the far end of the room. The projector screen against the wall whirred down to its extended position, and then retracted again. “Excellent!” the Doctor declared. “Good as new. Better than, in fact, since when it was new I got it second-hand. Sometimes it just needs a good cleaning-out on the insides; you’d be amazed the sort of muck that can build up in there.”

He strode over to Steve, pocketing the screwdriver, and clapped him on the arm. The Doctor’s expressive face drew down into solemn lines. “What you said before, about losing people,” he offered, “I understand.”

“You’ve…?” Steve started to ask, but trailed off; he already knew the answer.

The Doctor nodded. “Almost everyone. Home, friends, family; one way or another, gone.” He visibly shook himself, and put on another broad smile. “But that’s why you keep going! Always new places, new people, new adventures. Sometimes new screwdrivers! Not usually, though,” he amended. “Mostly you have to make do with a couple of paper clips, a bit of string, and a banana.”

Steve decided not to ask. He had a debriefing to focus on. _Any time now, Director…_


	6. Chapter 6

**Notes for the Chapter:**

> I really have too much fun writing Tony.

He heard his teammates approaching before he saw them; Stark's voice tended to carry. He and Banner brought up the rear of the pack, Stark holding a half-eaten donut in one metal gauntlet, and both of them arguing animatedly about something to do with science that Steve didn't follow. He guessed that it was about time travel, though, since Stark didn't seem likely to stop gnawing on that particular bone any time soon.

Barton and Natasha preceded them through the door into the briefing room, the archer licking powdered sugar from his fingers as he dropped into a seat at the conference table. "Hey, Cap," he greeted Steve, "told you I'd round 'em up in no time."

"Thanks, Barton," he replied. The time-out seemed to have done the team some good; even Natasha looked marginally more at ease, though Steve knew that it might simply have been another of her masks. She was looking at him expectantly. "Agent Romanov?"

"Fury is on his way," she informed him. "We saw Agent Hill leave his office on our way back, and if they've finished going over the satellite images, he'll be coming to us for–"

"Avengers." The imposing form of Director Fury stood framed in the doorway. His eye swept the room. "Who can tell me what is wrong with this picture?"

Natasha Romanov never stood with her back to a door, so she wasn't precisely _startled_ by the sudden appearance of the Director, but the relaxed manner evaporated from her posture. "He's here on my authorization," she said evenly, gesturing at the laminated security badge dangling from a cord around the Doctor's neck. "He has information we need about these aliens."

Fury's eyebrows lifted. "Half your _team_ doesn't have clearance to enter this building yet, and you bring in a total stranger. This had better be some very good information, Agent."

"If you're interested in the large spaceship locked in synchronous orbit over the city, I expect you'll be rather pleased with what I can tell you," the Doctor announced.

The gazes of every occupant of the room fell on the man in the bow tie. Even Stark and Banner interrupted their argument about temporal physics to stare at him. "How do you know about that?" Fury demanded. "We only picked up sensor echoes showing an object in orbit ten minutes ago."

The Doctor smiled. "I know the Ketaros," he said simply. "They use the same procedure on all the worlds they select for energy harvesting."

Fury studied the strange man for a long moment, his face unreadable. "Everyone take a seat," he ordered, helping himself to one of the conference chairs. "Start from the beginning, Mr. …?"

"Doctor, actually."

The one-eyed glare told Steve that Fury's patience was wearing thin. "Doctor _who?"_

"Just 'the Doctor,'" chirped the man in question. "But I'm not what you want to hear about right now, am I? You want to know about the Ketaros."

"That's right," Fury agreed, "and the accuracy and usefulness of the information you give us will determine how pleasant our future conversations will be." He pressed a button on a small panel embedded in the conference table; Steve guessed that it activated some sort of recording or surveillance device. "Whenever you're ready."

Rather than sitting, the Doctor began to pace the conference room. "The Ketaros are a highly technologically-advanced race native to the Pythia Cluster, a part of space that was once rich in energy resources." His tone carried a hint of the smug pedagogy that had colored his discussion with Stark about the time machine. "As the Ketaros civilization expanded throughout the sector, they consumed those resources at a rapid pace, to power the machines on which their society depended. Soon they faced an existential crisis, as the energy that powered their civilization began to dry up."

"And they said my work in clean energy wasn't as important as the defense contracts I was giving up," Stark griped.

"We're all very impressed with your civic-mindedness," Barton drawled. "Now shut up – it's story time."

The Doctor continued on as though he hadn't noticed the interruption. "For the solution to their problem, they looked to their own biology. Just as the sails on their backs absorb heat from the suns to regulate their body temperature, the technology they developed enabled them to absorb a variety of types of energy, which they could then convert to power their cities and ships."

"Like a dimetrodon," Stark observed. "We're being invaded by Dinosaurs from Space?"

"The dimetrodon wasn't a dinosaur, Tony," Banner interjected. "It was a synapsid – a proto-mammal, and it went extinct several million years before the start of the Mesozoic Era, when–"

"Save the Mister Wizard hour for some time when we're not trying to fight off an alien invasion, kids," Fury snapped. "Go on, Doctor."

The Doctor nodded, straightening his bow tie before continuing. "They began sending out collection ships to other parts of space, homing in on planets where they detected the presence of intense energy production and output. Their collection devices would gather and store the energy they found, holding it until they could return to the Pythia Cluster with the power needed to run their worlds. They can siphon off and store an entire planet's supply of energy in a single ship."

"You're shitting me," Stark declared. "You have _got_ to be shitting me, because otherwise we're being invaded by _Con Edison_. Half the reason I installed the arc reactor in Stark Tower was to get their damned meter-readers out of my hair, and now I've got to deal with their space-dinosaur doppelgangers?"

"I _will_ make you sit in the hall until this briefing is over, Stark," Fury growled. Stark subsided, grumbling.

"Does that mean we can expect more teams like the one we encountered in the subway?" Natasha asked.

The Doctor shook his head. "Not many. Since the Tesseract is no longer available – which is probably what drew them to Earth in the first place – they were looking for alternate power sources to drain. But it shouldn't take long for their ship-board sensors to pinpoint the largest energy supply in the area..." His eyes went wide, and silence reigned in the conference room for an instant, before he and Stark shouted at once:

"Stark Tower!"

"The TARDIS!"

Both men rushed to the window; Stark yanked on the cord that controlled the Venetian blinds. Steve could see over Stark's shoulder exactly what had the two of them in a near-panic: a narrow thread of blue-white light lanced down from the sky to pinion Stark Tower. No lights showed in the building.

The Doctor tore himself away from the window first. "I have to get over there! The TARDIS was already running low on power – that's why I was heading for Cardiff. Her shielding won't protect her for long!"

Steve caught the Doctor's arm as the smaller man tried to rush past him on his way to the door. "Doctor, wait. We need a plan to deal with that thing." Gently, he added, "We can help."

"All right, yes, a plan," the Doctor agreed. He frowned. "Seems a bit back-to-front, though; usually I don't know what my plan is until I'm halfway through with it."

"You said the ship in orbit has sensors?" Banner asked. At the Doctor's nod, he continued. "Then they'll probably detect any effort we make to interfere with the beam, or to go after the ship itself. If we even _had_ a way of getting up into space." Each of the Avengers glanced pointedly at Fury, who didn't appear to notice.

"Could the Ketaros redirect their collection beam at us, if we tried anything?" Natasha's demeanor had shifted; she was the Black Widow, focused solely on the mission before her. "For that matter, what exactly are the capabilities of that ship up there? Weapons, defenses, crew complement?"

"Without the TARDIS's data banks, I can't offer too many details," the Doctor explained. "Ketaros collection ships are designed to operate from orbit, and so the undersides are heavily shielded from any planet-based attack. Their only vulnerable point is on the top of the ship, where the energy storage capacitor is."

Stark drummed his metal-sheathed fingers against the window pane thoughtfully. "What would happen if we hit them with their own tech?" he asked, nodding at the glowing white needle spearing his skyscraper.

"That would depend entirely on where you targeted them," the Doctor replied, his voice taking on a similarly speculative tone. "From below, the ship's shielding would simply disperse the beam. If you could hit the capacitor, it would completely destabilize the storage matrix, and their accumulated energy would blast the ship apart. I doubt the hand-held energy collectors the scouting team carried would be powerful enough for that, though."

Steve had been listening with half an ear while replaying the subway fight in his head, trying to find some advantage to use against the aliens. His head snapped up, drawing the room's attention to him. "My shield!" he declared. "I was able to reflect their weapon discharge before. I could probably do the same with the beam targeting the Tower."

"It'll still splatter against their shielding," Stark remarked, shaking his head. "We'd need a second reflector, positioned above their ship's orbit. Reflect the beam up at an angle, past the edge of their ship, and then bounce it back down on their heads." He made vague twitchy gestures with his right hand. "Marker," he said to Banner, pointing behind chair where the other man sat. Banner reached back and snatched a blue marker from the white-board tray behind him and tossed it to Stark, who immediately began sketching angles on the window glass.

Glancing from the battle-scuffed disk he carried to the Doctor, Steve asked, "Will anything else be able to redirect the beam? When Howard gave me this, he told me this was all we had of the metal it's made from. Unless we've gotten more since then?" He glanced at Fury, who shook his head.

The Doctor reached for his shield. "May I?" Steve nodded and passed it to him with only a little reluctance. The Doctor flicked its surface with one finger, putting his ear close to the metal to listen to the result. "Vibranium! Just as I thought." He handed it back to Steve. "No, I'm afraid that's the only thing that will do the job. Most metals either absorb the collectors' energies, or let them pass right through."

"So much for that idea, then," Steve sighed, leaning against the wall. "My shield can't exactly be in two places at once."

The Doctor stared at him, a wide smile breaking across his expressive face. "Of course it can!" he laughed. "I distinctly recall an occasion when I was in _five_ places at once!" He rolled his eyes at the blank stares that greeted that announcement. "I did mention the _time machine_ , didn't I?"

"Are you saying... what I think you're saying?" Barton asked – much to Steve's relief, since it meant Steve didn't have to say it himself.

"No, no, I see what he's saying, this can work!" Stark cut in. He brandished his marker at the window again, before realizing that he'd taken up the entire pane with his diagram. He shrugged and moved to the wall beside it. "Here's you, traveling through time the normal way, one moment after the next." He drew a straight horizontal line across the wall, completely ignoring Director Fury's spluttered protests about defacing SHIELD property. "Then you hop in your time machine," he zig-zagged the line down and backward, "and you travel to a different place, a couple of minutes back in time from when you left." He continued with another horizontal line, parallel to the first. Then he pointed a gauntleted finger at the first line. "This is you on the roof of Stark Tower," he explained, and jabbed the second horizontal line. "And this is you up in space. How do we get him up in space, Doc?"

"The TARDIS is also a spaceship," the Doctor offered casually.

Stark blinked. "Of course it is."

"Then it's just a matter of getting to the roof," Natasha observed, bringing them back on task. " _Can_ the aliens redirect their weapon to take out any transport we send up there?" The question had acquired a barb since the first time she'd asked it without getting a response.

The Doctor nodded. "They could widen the beam, which would amount to the same thing. Right now it looks like they're using the narrowest possible setting, since they've found a nice, tasty energy source and want to drain it as quickly as possible. They could expand the radius of the beam significantly to employ a less efficient collection over a much wider area, which would still be enough to take out most powered vehicles."

"Then I guess we'll have to rely on non-powered transportation," Steve said, heading for the door. "You ready to run, Doctor?"

He received an enormous grin in response. "Always."


	7. Chapter 7

**Summary for the Chapter:**

> In which there is running...

Steve pulled his motorcycle up in front of Stark Tower. The architecture, with its smooth, futuristic lines and its integrated electronics everywhere, was in some ways a clearer signature of Tony Stark than the giant lighted letters had been. That made it strange, and a little eerie, to see the building entirely without power. Lit only by the sun, it seemed empty and dead, like a dried-out seashell.

The Doctor hopped off the back of the motorcycle behind him as he parked on the sidewalk, and they both headed for the main entrance. The glass-paneled door swung open as Steve reached for the handle, and a dark-skinned woman in a business suit nearly walked into him, as she was too focused the mobile telephone in her hand to notice him right away. Her head jerked up, startled, at his, "Excuse me, Miss."

"Oh, sorr– Oh!" She looked from his face to his conspicuously iconic uniform and shield. "Captain America? Is something wrong – does it have to do with the blackout? Are we being attacked again?" Her eyes were wide, and she gripped her telephone tightly.

"Everything will be fine, Miss." He took her arm and gently guided her out of the doorway. "I'm going to take care of it now. Can you tell me what's going on inside?"

He managed to inject the right combination of calm and urgency into his voice to steady her; she took a breath and nodded. "There's no power anywhere in the building. Everything is down: elevators, land lines, even the emergency lighting. None of the backups have come on. People are nervous, but I don't know of any emergencies yet. It's mostly only repair crews and a skeleton staff on the business levels right now. I came outside to try and get cell reception, to contact Mr. Stark or Ms. Potts; reception is awful in this building."

Most of what she told him, Steve already knew, or had guessed, but he quickly picked out the most important bits of information: no one was seriously hurt, and this woman was important enough to have a direct line to Stark and Ms. Potts. That meant others here would take orders from her. "What's your name?"

"Sumati," she replied automatically.

He nodded. "Okay. Sumati, here's what I need you to do. Come back inside with me, and make a round of every occupied floor. Tell everyone to stay calm, keep away from electrical equipment and outlets, and sit tight. People are only going to get hurt if they start stampeding down the stairs when there's no immediate danger. Reassure them, and keep them busy. I'm going up to the roof to deal with what's causing the problem."

She stood a little straighter. "I can do that, Captain." She turned and preceded him back inside the building. "If you're headed for the roof, you'll want the red stairwell; it goes straight up to the living quarters. The entrance is on the tenth floor, in R&D. If you take this staircase," she pointed at a blue metal door tucked into a small alcove beside the bank of darkened elevators, "you can get up to floor ten. Normally you need an access card for the red stairwell, but with the power out," she shrugged, "you'll probably need to break past the emergency deadbolts."

"The doors won't unlock with the power off?" Steve asked.

Sumati shook her head. "The regular locks are magnetic, but the emergency deadbolts run on a pneumatic spring; an electromagnetic switch keeps them disengaged. When the power is cut off, they lock down the doors automatically. The same locks have been installed on all the sensitive laboratories. Mr. Stark takes security very seriously."

Her comment about the laboratories caught Steve's attention. "Are there people trapped in the labs? Will they be all right?"

Her mouth narrowed to a thin line. "If you're fast. There's no power to the ventilation system, but the labs have high ceilings. They should be safe for several hours, at least."

"Good. Then we've got work to do," Steve said, heading for the blue stairwell door.

Sumati gave him a tight smile. "So do I." She headed down the main hallway, her heels echoing on the linoleum floor. Steve had just opened the door to the stairs when he heard her footsteps pause, and glanced back at her. "Try to find some light," she called to him. "I nearly broke an ankle coming down those stairs!"

"Will do," he replied with a wave, "thanks!"

When the door swung closed behind him and the Doctor, Steve found that her advice had been more than apt; with no windows other than the small one in the stairwell door, and no artificial light sources, it was like walking into a cave. He paused, letting his eyes adjust to whatever faint scraps of light existed, and the Doctor immediately bumped into his back.

"Sorry. It's a bit dim in here," the Doctor said, and a whirring sound made Steve glance back over his shoulder. The Doctor's face was illuminated by a faint green glow emanating from the tip of his screwdriver. "No, not quite enough," he said, fiddling with the buttons on the side of the device. The glow brightened noticeably. "That's better!" The Doctor held the screwdriver out at about shoulder level, its light revealing the staircase. "There. It's not quite a torch, but it'll do." He looked at Steve. "You said there'd be running?"

Steve nodded. "Let's go." He charged up the stairs. The serum had improved his night vision, but he was neither a cat nor one of those infrared lenses Barton talked about using on stealth missions, so Steve made sure to stay within the circle of green light cast by the Doctor's screwdriver. Fortunately, the other man was keeping up a fair pace.

At the end of nine flights of stairs, that pace was starting to flag, at least for one of them. When Steve pushed open the door marked "10," the Doctor leaned heavily against the doorjamb, the arm bearing the screwdriver drooping. "You doing all right, Doctor?" Steve asked.

"Sure," the Doctor managed between labored breaths, "It's just that most of the time when I'm running, it's more," he gestured sloppily with his free hand, "horizontal."

"Well, you can take a breather, since I'm gonna have to break through the deadbolt on the door into the other stairway. When I find it," Steve added, casting a glance down the hallway they'd emerged into.

"Might be able to help," the Doctor offered, waving his screwdriver. He took a few deep breaths; it seemed that he was already starting to recover.

"Doing better?"

The Doctor patted his chest. "Two hearts," he explained. "Makes this sort of thing a little easier."

Steve looked at him and grinned. "You know, when all this is over, I'm going to start actually _thinking_ about all the things you've told us about yourself, and be very confused. Come on," he said, striking off down the corridor. "We should keep going."

"Right!" The Doctor pushed off from the door-frame and followed Steve, holding the screwdriver out in front of them as they went.

One right turn and about twenty yards later, Steve noticed something, and held out a hand to stop the Doctor. "Wait. What color is that door?" He pointed at one that was a different shade than the rest of the doors they'd passed; in the green light of the Doctor's device, it looked an unflattering brown.

"I think this is our stop," the Doctor replied, crouching beside the door handle. He gave it a tug, and met with solid resistance. "That's the one, all right: pneumatic bolts. Give me half a tick." He bent over the screwdriver, pressing buttons in rapid succession. The light dimmed back to its usual levels, and the whirring sound it emitted rose and fell in pitch. "Just a second... Ha!" Steve heard a metallic clanking sound from inside the wall, and the door swung slightly ajar.

Then they were running again. The Doctor had the green light from his screwdriver shining brightly again halfway to the eleventh floor. The walls reflected the same muddy brown as the door, a color that Steve's eyes were learning to interpret as "red." The only sound in the stairwell was the rapid rhythm of their feet pounding the metal stairs as they climbed from one floor to the next. As he rounded a landing to reach another flight of stairs, Steve glanced behind him at his companion; though the Doctor didn't seem as tired as before, his mouth was set in a grim line, and a crease had appeared between his brows. "What's wrong?"

"The TARDIS." The Doctor's voice thrummed with tension. "I don't know how much longer her shielding can hold out – if it hasn't collapsed already." There was a pause that Steve didn't think had anything to do with the strain of their ascent. "This could kill her."

Steve wasn't sure how to respond to that; rather than try, he kept running. Still, something confused him about what the Doctor had said, and his mind wouldn't leave the question alone. "The TARDIS, it's a machine, right?" he asked after another couple of floors had gone by under their feet. "You talk about her like she's alive."

"She is," the Doctor replied. "TARDISes aren't built, they're grown." After a moment, he continued. "Rather, they _were_. She's the only one now." They passed another two floors. "She's all I have left of home. She's been with me since the beginning; the only one who's never left. There were times I thought she was gone – lost, taken, even destroyed – but she always came back."

"We'll get there in time, Doctor." It was the only thing there was to say.


	8. Chapter 8

The penthouse looked just as it had earlier that morning, when Ms. Potts had sent him up in the elevator to look for Stark. One of the big windows, to one side of the bar, was completely shattered, and part of the slate floor looked like someone had taken a jackhammer to it. Otherwise, the residence had suffered little damage in the previous day's battle. Plenty of sunlight streamed through the huge windows, and Steve briefly shaded his eyes to give them a chance to adjust to the brighter space. The Doctor brushed past him, darting for the door that let out onto the roof. As soon as he was no longer half-blinded by the daylight, Steve followed.

The torrent of crackling blue-white energy that streamed down from the sky was narrower than Steve had expected; rather than taking up half the roof, it was maybe a yard in diameter. Part of the beam clipped one corner of the blue police call-box, and the rest streamed down its side to penetrate the roof beneath. The Doctor was already standing beside the TARDIS, with one hand on its door. "She's still alive!" he cried as Steve approached. Relief cut through the undercurrent of worry in his voice. "Her power reserves are low, but they should be enough. Hurry!"

Steve nodded, adjusted the fit of his shield on his arm, and took a running start. _Don't overshoot, Rogers,_ he told himself as he pushed himself off the concrete and into the air, _it's a long way down._ The top of the TARDIS was only about three feet across, slightly sloped, and had a light sticking up out of the center – but Steve had made more improbable leaps that week. His mind helpfully supplied the image of the Helicarrier's damaged turbine, and the feeling of dangling from a cable over thousands of feet of empty air. _Yeah, let's not do that again._ He dropped to one knee for stability, wrapping his free right hand around the light fixture jutting from the TARDIS's roof, and lifted his shield up into the energy beam.

The column of energy exerted a surprising amount of force on his shield – though oddly, he felt it pulling _up,_ not pushing _down._ Static prickled at his skin and hair, and he had to squeeze his eyes mostly shut against the painful brightness, but the force of the beam wasn't enough to shift his arm out of position. Turning his forearm, he tilted the shield slightly, knowing that even a minute change in angle down here would dramatically affect where the beam reflected out in space. He spared a moment's thought for all the man-made satellites he'd been told were up in orbit now: communications, surveillance, global positioning. _Hope I don't wing one of them,_ he thought, squinting up at the sky.

"Just a couple of degrees more to your right, Captain," he heard the Doctor call to him from below. He tipped his shield a little further to that side. "No, that's a bit too much; bring it back just a hair," came the next direction. Steve made the adjustment. "Yes! Good! Now hold it right there for a bit, give us a good long window to get into position." Steve nodded, then focused on keeping his muscles perfectly still, concentrating on the rhythm of his breathing. He wasn't sure exactly how much time had elapsed when the Doctor called to him again. "That should do it. Now, we're going to have to time this carefully, because we can't take off while the energy collector is draining the TARDIS's reserves. When I yell, you need to get inside _fast._ Got it?"

"I got it," Steve said, twisting his neck around to look down at the Doctor. "But shouldn't the alien ship have blown up already, if the plan works? I mean, we go back in time a couple of minutes, so shouldn't we be seeing the results of what we're about to do?"

The Doctor shook his head. "That's not how time works. You'd think it would, but it doesn't. Time isn't linear and deterministic that way; when viewed from outside the time stream, it's really more like a big ball of – never mind, I'll explain later. Get ready!" He slipped what looked like a perfectly normal key into the lock and ducked inside the TARDIS, leaving the door swinging open.

A moment later, the light knob Steve was gripping winked on, and some profoundly odd noises drifted out through the TARDIS door. Following them a second later came the Doctor's voice: "Now! Inside! Now!"

Steve dropped his shield arm and threw himself backwards, grabbing onto the edge of the TARDIS roof with his right hand. He used the force of his momentum to swing himself through the open door, landing in a sprawl on the floor inside. The door snapped shut of its own accord behind him. Steve pushed himself to all fours and looked around.

The room was both enormous and bizarre. It reminded him of something out of H. G. Wells – futuristic in a way that was entirely different from the sleek lines and polished chrome of the future he lived in now. What Steve guessed was the main console was a giant wheel of buttons, levers, switches, and more esoteric controls that hinted at functions that were less than obvious. Most impressively, the room was significantly larger than the police call-box he'd just been standing on top of.

"It's... bigger than I expected," he observed mildly.

The Doctor grinned down at him from the main console, where he was piloting the TARDIS – or so Steve assumed; the man was darting around spinning dials and pulling levers in what appeared to be an entirely haphazard fashion. "I know! Isn't it smashing?" He peered into a small monitor, and made some adjustments to something outside of Steve's line of vision. "I'm calculating the optimal position for reflecting the energy collector's discharge at the Ketaros ship without putting the TARDIS in the direct path of the beam," he told Steve. "Your turn will be up shortly."

Steve glanced at the door, hefting his shield. "So how exactly is this gonna work?"

"The TARDIS projects a bubble of atmosphere around herself when the door is open," the Doctor explained. "You'll be able to lean out and catch the energy stream as it passes by. Though you may want to fasten yourself to something."

Steve nodded and moved into position. He found several narrow exposed pipes to one side of the door, and clipped one of his uniform straps to them. Giving it a tug, he decided it was secure, then turned back toward the Doctor. "You'll let me know when we're in position?"

"Nope," the Doctor replied, still grinning, " _she_ will."

Sure enough, the door swung open by itself a few seconds later. A few feet away, the now-familiar energy beam shot past, and beyond it to his left, Steve could see the alien ship. This far into space, there was no frame of reference to make an accurate estimate of its size, but he could tell that it significantly dwarfed the Helicarrier. The TARDIS was slightly above the other ship, and Steve could readily identify his target: a large cylinder that jutted above the otherwise relatively uniform surface of the ship.

It was an unsettling feeling, leaning out of the shelter of a spacecraft and into the void. He grasped the door-frame tightly with his right hand, and kept his right foot firmly planted on the floor inside the TARDIS. The strap that tethered him stretched taut as he leaned out as far as he could reach. He brought his shield up into the path of the beam, twisting his arm around until the redirected shaft of light struck the Ketaros ship. Small movements of his muscles focused the ray on the storage capacitor; when he had the target painted, he held steady.

Almost immediately there was a reaction from the ship. Lights across its surface died and flared back to life in rapid succession. Tremors, tiny at first but rapidly increasing in intensity, rocked the alien craft. "What if they shut off the beam?" he shouted over his shoulder.

"Then they will have given up on Earth, and can go bother someone else," the Doctor replied. "They have the chance to surrender and leave peacefully, if they're smart enough to take it."

That seemed unlikely, from where Steve was standing. He could see the storage capacitor starting to glow an angry orange-red, and the Ketaros spaceship shuddered violently. His final warning was seeing the huge cylinder crumple in on itself; he pulled himself back into the safety of the TARDIS just as an enormous flash of light burst across his vision. The door slammed shut behind him.

Sound didn't carry across the vacuum of space, but the shock wave of the blast rocked the TARDIS, and only the strap tethering him to the pipe enabled him to keep his feet under him. The Doctor clung to the console, barely managing to keep from being tossed about the chamber. When the ship settled, the Doctor punched a couple of keys on a control panel and looked into one of the screens. "The Ketaros ship has been destroyed, and none of the debris is large enough to make it through the atmosphere," he declared.

Steve slumped against the wall, relief washing over him. He was never one for celebrating the deaths of his enemies, but many more people would have died on Earth if the Ketaros hadn't been stopped. Even counting only the number of people currently relying on artificial life support, the casualties would have been... He shook his head. It didn't matter; they were safe now. "We should head back," he said wearily. "Fury and the others will want to know what happened."

A wry smile broke across the Doctor's face. "In a moment, they'll be more interested in knowing how the TARDIS was able to materialize inside their top secret headquarters."

Whether it was the post-battle release of tension, or the mental image of the expression on Fury's face, Steve wasn't sure, but it was a good three minutes before he could stop laughing.


	9. Chapter 9

**Notes for the Chapter:**

> Last chapter!

"End call," he told JARVIS, and pulled the helmet off his head. He checked his hair in the mirror over the line of sinks, threw a flippant salute at the security camera in the corner of the ceiling, and stepped out of the men's room. The corridor was pale beige, with a steel-gray carpet just padded enough to muffle the footsteps of agents scurrying off to accomplish whatever missions or assignments or errands The Great And Powerful Oz had sent them on.

He followed the route he had seen the others take as Fury had led the way to one of the "tactical observation rooms" – the way people around here avoided using the term _war room_ was amusing, in a charmingly superstitious kind of way. Tony was personally of the opinion that one group attacking another for control of a valued resource fit the textbook definition of "war," but if avoiding the word helped them sleep at night, he couldn't exactly throw stones when it came to dodging self-evident realities for the sake of psychological comfort.

They'd left the door cracked open for him – considerate, since the lock was controlled by a retinal scanner. He palmed it open and strolled inside, offering a slight grin as all eyes turned to him. "Sorry, had to powder my nose," he offered in lieu of an explanation, "what'd I miss?"

"No change yet," Romanov told him, glancing back to the main screen, which displayed a live feed of Stark Tower. He tried to place where the camera was positioned, based on the angle of the shot; it wasn't quite even with the roof, but it couldn't have been more than twenty floors down, and there were no other buildings blocking the bottom of the image. Inside one of the offices across the street, then. And that damned lance of energy was still stabbing straight down into his roof. He tore his eyes away from the monitor to look at Romanov as she continued. "Without any power to the elevators, they'll need to get to the roof on foot, which will take time even for the Captain."

"I know; I've just never been very good at the whole 'waiting' thing, and – hold on!" His gaze snapped back to the screen, and he moved closer to it. The column of light in the image had changed. It seemed wider up toward the top edge of the monitor. He turned to Fury, keeping one eye on the screen. "Have your camera guy angle the shot higher. Something's happening."

Fury stared at him for a long moment, then nodded. He touched a button on the comm panel beside him. "Raise the angle of the image. We need to see farther up." A moment later, the picture on the monitor obediently panned upward. At the extreme edge of the camera's vision, Tony could just see the point where the glowing beam split in two, before disappearing against the bright blue backdrop of the sky.

"They're doing it," he whispered. He was standing beside the monitor now, eyes fixed on the image of the bright strand of light. "Come on, Cap, you can do this." His metal-sheathed hands flexed and opened unconsciously. _I should be out there,_ he thought. _Stupid electricity-vampire space dinosaurs._

He realized he'd been holding his breath, and exhaled. The upper corner of the screen held a clock, where hundredths of a second were constantly cycling by, making the set of numbers just to their left seem to tick by at a ploddingly slow rate. The counter cycled through more than a full minute before the glowing thread of light vanished from the screen. "Bring the camera back down!"

Fury was already on the comm with the camera operator, and the image swooped back to the rooftop. At mid-afternoon, few lights would show through the windows of any corporate building, but the _A_ that was all that remained of the Tower's name glowed brightly against the darker platform.

Tony groped blindly behind him for an empty chair, and someone – _probably Bruce, he's a real pal like that_ – kindly slid one under his hand. He sank down into it in relief. "He did it." He felt himself grinning.

"Sir," Romanov cut in, addressing Fury, "the orbital scanners are no longer reading the Ketaros ship. They _are_ picking up what looks like a meteor shower, though none is expected at this time of year."

"A meteor shower?" Barton asked.

She turned to him and nodded. "Yes: a cloud of small fragments of space debris being incinerated by entering the Earth's atmosphere."

"Oh, _that_ kind of meteor shower."

The door opened, and Tony swiveled his chair to see Agent Hill standing just inside the room, looking concerned. "Sir, we've got an internal security alert." Fury turned to glare at Tony.

He raised his hands defensively. "Hey, I did nothing! I went to the _can._ That's allowed, isn't it?" _And I made a phone call, but that shouldn't have set off anyone's oversensitive security systems. Not five minutes later, anyhow._

The Director turned his attention back to Hill. "What are we dealing with, Agent?"

"A door on Level Three were opened without a pass-card or ID scan," she replied. "We've got security _en route,_ but given recent events, I thought it best to keep you informed, sir."

Barton turned to Romanov, pointing down at the table. "Aren't we _on_ Level Three?"

"Excuse me, ma'am," came a familiar voice from behind Hill.

She whirled around, one hand dropping to her sidearm, but relaxed when she saw who was standing there. "Captain Rogers? How did you …? No one picked you up entering the building."

Cap shrugged. "Turns out the Doctor's time machine isn't just a spaceship; it also teleports." He blinked. "That was a weird sentence."

Tony rose and approached them, stepping around Hill to clap a hand on Cap's shoulder. "Try not to think about it too hard," he advised. "If we keep hanging around with this crew, things are only gonna get weirder."

"The security breach was you?" Hill interrupted. "The door seal that was circumvented–"

"We, ah, sort of parked the TARDIS in a utility closet," the Doctor confessed, squeezing past Cap into the room. "I hope we didn't cause too much of a fuss."

Hill rolled her eyes and raised a hand to the headset at her ear. "Security team stand down. The intruders have been identified and," she sighed, "contained."

"Director," the intercom at Fury's elbow blurted, "there's a man at the front gate who says his name is Mr. Hogan, and is insisting to be admitted to see Mr. Stark."

Tony leaned over Fury's shoulder just as he pressed the intercom button to respond. "Yeah, that's Happy – send him right on up; I asked him to bring something for me."

Fury glowered at him, and sighed into the intercom. "Go ahead, let him in and have him escorted to Tactical Observation Four." He twisted his chair around and leveled his glare at Agent Hill. "What the hell is this – did somebody announce SHIELD Headquarters Open House Day and not tell me about it?"

The corner of Hill's mouth twitched. "Not that I'm aware of, sir."

It wasn't long before Happy joined the group assembled in the war room, carrying a small cardboard box and trailing an agent wearing a suit and an earpiece. Completely undaunted by the important-looking and dangerous people surrounding him, Happy strode right up to Tony and offered him the box. "Here you are, Mr. Stark."

Tony grinned at him. "Thanks, Happy." He flipped open the lid, looking down into the box with an uncomfortable mix of emotions that he didn't want to examine too closely. Then he approached the Doctor, who was apparently explaining something to Fury and the agents that involved a lot of wild gesturing.

"Hey, Doc," he interrupted, "I've got something for you."

The Doctor turned to face him, his expression curious. "And what might that be?"

"Well – bearing in mind that I still want to see that time machine of yours before you go disappearing with it," Tony insisted, "I remembered you mentioned that it was running low on power, and while I don't know if the systems will be compatible, or even if this is anything like the kind of power your time-machine-spaceship-teleporter runs on, because seriously, scientists on Earth can't make up their minds about whether time travel is even a _thing,_ let alone how to power it – I thought maybe you might be able to use this as kind of a jump-start, until you could get somewhere that had the right sort of fuel." He thrust the box into the Doctor's hands. "It's one of my old palladium reactors; doesn't do me much good anymore – I learned that lesson the hard way, let me tell you," he patted the triangle of light on his armored chest meaningfully, "but maybe you can get some use out of it. Or not – I mean, if you don't think it'll help, I can always just–"

The Doctor reached into the box and pulled out the tiny arc reactor. Setting the box on the table, he turned the device over in his hands a few times, then looked up at Tony and smiled. "I think this will do just swimmingly to keep the TARDIS going until I can recharge her energy reserves. Thank you."

"Great! So..." Tony tried to keep the eagerness out of his voice, but really, who was he kidding? _Time machine._ "Do I get to see it?"

"Absolutely! You can even help me adapt your device to the TARDIS's power matrix. Come on, no time like the present," the Doctor replied, heading for the door. He grabbed Cap's arm on the way, dragging him with them into the corridor. "That reminds me, Captain, I wanted to ask you something."

"Yes, Doctor?"

"I think your friend here will be thrilled to bits at the opportunity to poke around the TARDIS's systems with me, but I was thinking you might prefer something else." He paused in the hallway and looked up at Cap. "Would you like to go for a trip? Anywhere in time and space – what do you say?"

The expression that broke across Steve's face was one that Tony had never seen the soldier wear, and it took him a moment to identify: it was joy. "I – yes! I'd like that. Thank you!"

A knowing smirk curled the Doctor's mouth. "I take it you already know where you'd like to go?"

Steve nodded. "I promised a lady a dance," he said simply, his smile making him look much younger and less careworn than the Captain America that Tony had come to know. "I don't want to keep her waiting."

**Notes for the Chapter:**

> And so ends Part One of Three. The next story, _One Single Yesterday,_ is still in the works, and will be starring Peggy Carter. Stay tuned!


End file.
